18) Conditional Statements

♣    Whenever we want to execute a single statement or block of statements based on some condition then we will implement conditional statements

♣    In C#.net we can implement two types of conditional statements

                      1. IF Condition

                      2. Switch Condition

IF Condition :

♣    If Condition we can implement in 3 ways

                 1. IF

                 2. IF Else

                 3. IF Else IF

# IF :

♣    Syntax is like below

      if(condition)
      {
            statement 1;
            statement 2;
       }

Example for Just IF

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace pro9
{
    class Program
    {
        static void Main(string[] args)
        {
            /*simple if */
            Console.WriteLine("Enter First No");
            int n1 = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Enter Second No");
            int n2 = Convert.ToInt32(Console.ReadLine());
            if (n2==0)
            {
                Console.WriteLine("Enter Other than zero");
                n2 = Convert.ToInt32(Console.ReadLine());
            }
            int res = n1 / n2;
                Console.WriteLine("Result is"+res);
            Console.ReadLine();
        }
    }
}

Output :

# IF Else :

♣    Syntax is like below

     if(condition)
     {
        Statement 1;
     }
      else
        {
           Statement 2;
        }

Example to compare two numbers

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace pro10
{
    class Program
    {
        static void Main(string[] args)
        {
            /*simple if else*/
            Console.WriteLine("Enter First No");
            int i = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Enter Second No");
            int j = Convert.ToInt32(Console.ReadLine());
            if (i > j)
                Console.WriteLine("First Numebr is grater than Second Number");
            else
                Console.WriteLine(" Second Number is grater than First Numebr");
            Console.ReadLine();
        }
    }
}

Output :

# IF Else IF :

♣    Syntax is Like Below

       if(condition)
        statement 1;
        else if(condition 2)
        statement 2;
        else if(condition 3)
        statement 3;
       else
       statement 4;

Example for IF Else If

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace pro11
{
    class Program
    {
        static void Main(string[] args)
        {
            /*if else if which is grater no */
            Console.WriteLine("Enter First No");
            int i = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Enter Second No");
            int j = Convert.ToInt32(Console.ReadLine());
            if (i > j)
                Console.WriteLine("First No is grater than Second No");
           else if (i < j)
                Console.WriteLine(" Second No is grater than First No");
            else
                Console.WriteLine("First No, Second No both are equal");
            Console.ReadLine();
        }
    }
}

Output :

Switch Condition :

♣    Whenever we want to execute single case among multiple cases we will go for switch condition

♣    Syntax is like below

     Switch(<expression>)
     {
         case 1:
                   statement 1;
                   break;
        case 2:
                   statement 2;
                   break;
       case 3:
                   statement 3;
                   break;
     Default :
                   statement 4;
                   break;
      }

Note : Break is a C#.Net keyword, once break statement is executed control will not execute any other statements with in the switch block, it will transfer to out of the switch block.

Example for Switch Condition

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace pro12
{
    class Program
    {
        static void Main(string[] args)
        {
            /*example of switch case month no to name*/
            Console.WriteLine("enter month no");
            int no = int.Parse(Console.ReadLine());
            switch (no)
            {
                case 1: Console.WriteLine("jan");
                    break;
                case 2: Console.WriteLine("feb");
                    break;
                case 3: Console.WriteLine("mar");
                    break;
                case 4: Console.WriteLine("apr");
                    break;                
                  case 5: Console.WriteLine("may");
                    break;
                  case 6: Console.WriteLine("jun");
                    break;
                  case 7: Console.WriteLine("jul");
                    break;
                  case 8: Console.WriteLine("aug");
                    break;
                  case 9: Console.WriteLine("sec");
                    break;
                  case 10: Console.WriteLine("oct");
                    break;
                  case 11: Console.WriteLine("nov");
                    break;
                  case 12: Console.WriteLine("dec");
                    break;
                 default: Console.WriteLine(" enter no 1-12 only");
                    break;
                  
            }
            Console.ReadLine();
        }
    }
}

Output :